The present invention relates to a method and apparatus for the manufacture of plastic storage containers and particularly folded flat plastic bags with an integrated formed standup bottom wall structure to provide a stand up plastic bag.
Common plastic bags are widely used in the packaging of products at the point of sale. The weight of the plastic and the construction will vary somewhat with the particular application, and particularly dependent upon the required strength of the bag. Such bags are used as an alternative to paper bags which are also folded members and specially formed with a bottom structure which, when the bag is opened, permits the direct standing of the paper bag to receive the product.
Plastic bags which will stand have not generally been available, particularly at a competitive cost. The assignee of this application is an owner of various pending patent applications disclosing a plastic bag construction which permits a folded flat plastic bag to be opened and with a substantially flat bottom wall permitting direct standup of the plastic bag. This latter bag has distinct advantages over the prior plastic bags which require the user to spend time to open the plastic bag and furthermore to place a product in the bag in order to even begin to provide a standup plastic bag construction.
As set forth in the following series of copending patent applications which included provisional applications and subsequent application and disclose various prior art and background information for this application.
Filing Ser. No. Date Inventor Title 1. 60/088,613 06-09-98 Robert DeMatteis Plastic Film Hinging 09/257,345 02-25-99 Robert DeMatteis Plastic Film Hinging Precreasing Process 2. 60/088,612 06-09-98 Robert DeMatteis Cold Sealing of Plastic Donald Pansier Film 09/257,848 02-25-99 Robert DeMatteis Apparatus and Process for Cold Seal in Plastic Bags 3. 60/089,582 06-17-98 Robert DeMatteis Plastic Bag Bundling System 09/258,010 02-25-99 Robert DeMatteis Plastic Bag Bundling (now U.S. System Pat. No. 6,171,226 4. 60/089,583 06-17-90 Donald Pansier Automatic Ventilating Robert DeMatteis System For Intake Bags 09/258,033 02-25-99 Robert DeMatteis Automatic Ventilating System For Intake Bags 5. 60/092,232 07-09-98 Robert DeMatteis Plastic Bag Donald Pansier Manufacturing Process 09/257,843 02-25-99 Robert DeMatteis Plastic Bag Donald Pansier Manufacturing Process 6. 60/092,233 07-09-98 Robert DeMatteis Plastic Film Donald Pansier Rigidity Means 09/258,015 02-25-99 Robert DeMatteis Plastic Film Donald Pansier Rigidity Means 7. 09/257,361 02-25-99 Robert DeMatteis Flat Bottom Plastic (now U.S. Bag Pat. No. 6,095,687
The applications when referenced herein are identified by the above numbers.
The above applications disclose various plastic bag structures, including one prior art patent disclosure of such bag with a flat bottom wall. Generally, the prior art plastic bag is considered complex to manufacture and still cumbersome in use.
The above referenced applications further disclose forming of a new plastic bag with a flat bottom wall by providing a hinge line pattern within the bag sides adjacent the bottom wall portion of a flat gusseted tubular plastic member. The unique bags which are disclosed in the above applications are generally formed with a top opening having a handle structure permitting the support of a stack of the bags for easy access and top opening. The bag may be opened rather easily by various methods. Thus, the one side of the bag opening may be grasped at the top and the bag snapped to provide the opening of the bag and the forming of the flat bottom wall. Merely reaching into the bag may also be applied to create the lay flat bottom wall condition.
Bag making machines are available for high speed production of the prior art plastic bags usually from flat folded or tubular plastic stock available in large rolls. The plastic stock is removed in its flat form and passed through the bag machine where it is cut and sealed to define a flat, open ended bag. The bags are normally formed in stacks and suitably packaged for marketing. The top opening may be shaped with a handle configuration with bags assembled in a stack. The stack may be joined along the upper edge or portion holding the stack together for subsequent handling. The stack may be supported on a hanger from which the merchant or purchaser can readily remove the outermost bag for inserting of product or products. As noted above, the prior art plastic bag which forms a relatively flat bottom wall has presented significant difficulty, and resulted in a relatively high cost bag.
The bag structure as disclosed in the copending application(s) provide a construction, which the present inventors recognized, is adapted to modification of the technology of known bag making processes. Existing modern high speed bag making machinery and technology provides a flat bag stock in tubular form and preferably of a width equal to the width of a plurality of bags. In the latter system, a wide web stock is severed and sealed along the length of the web stock to develop separate tubular bag lanes or lines which are then processed by appropriate sealing of the cut side edges to form individual tubular stock.
Other systems use a folded web with an open edge to form the opening to the bags and with the sides formed by side seams in the folded web.
The new design of the plastic bag with the hinged bottom wall structure requires special adaptation of the bag making technology to maintain a desired high speed and thereby low cost production of the new design. The hinge portion of the specially formed square bottom walls require accurate formation of a hinge within the folded web stock for forming of the bag and preferably with essentially minute seal lines in the bottom wall structure, and preferably sufficient to avoid interference with or requiring special handling to open the bag with the bottom formed as a direct flat supporting wall.